Pearse Doherty (Donegal, Sinn Fein) | Oireachtas source

We hear language here such as no hard border, customs controls and so forth. We also hear European language that is militarised - the language of hard customs controls in Europe where borders are actually armed, whereas soft borders are where there are just normal customs controls. What do we mean by minimising? What would have to happen in order to have no customs controls?